Transpiration-cooled incinerator



Filed Feb. 12, 1968 INVENTOR. ALAN B. CARSON @WQWW ATTORNEY UnitedStates Patent Oflice 3,478,706 Patented Nov. 18, 1969 us." or. 110-8Claims ABSTRACT OF THE DISCLOSURE This incinerator has composite wallsconsisting of an imperforate outer casing enclosing an inner casingformed with perforated walls spaced by a layer of air-pervious fireproofinsulating means, such as glass, metallic or mineral fibers. The outercasing is spaced from the inner casihg to form a manifold for receivingair under pressure which flows through the walls and insulation of theinner casing to support combustion and prevent outward fiow of heat. Thefibrous material functions first to reduce radiative heat flux, andsecond to permit inward air flow from the manifold to reduce heat fluxby conduction through the fibers and convection through the wall.Elongated heat dissipating elements yieldably space the inner gutercasings and the walls of the former are relatively movable so that theinner casing may expand and contract in response to thermal variations.Suitable shielding may be provided on or around the inner casing todissipate the heat and prevent direct heat radiation from the innercasing to the walls of the outer casing. Ignition and smoke burners andan exhaust stack also receive air from the air manifold.

Summary This invention relates generally to waste disposal; moreparticularly it is concerned with the incineration of the type ofwastegenerated in military or other kitchens designed to prepare foodrapidly for consumption by large crowds of individuals. Still moreparticularly, the invention is directed to a portable, substantiallyselfcontained incinerator, which is so constructed that it wilI be lightin weight compared to conventional structures, will have relatively coolexterior walls, will substaritially completely consume the wasteintroduced to it, have an extended useful life, and will require aminimum of care and attention.

An object of this invention is to provide an incinerator having an innercasing forming a combustion chamber enclosed in an outer casing with anair space therebetween to receive air under pressure, such air servingthe dual purpose of preventing heat transfer to the outer from the innercasing by conducting the radiative and convective heat back into theinterior of the inner casing and supporting combustion of fuel suppliedto ignition and smoke burners as well as the waste matter introducedinto the combustion chamber.

Another object of the invention is to provide an incinerator utilizingtranspiration cooling principles to maintain cool exterior walls andexhaust stack.

Still another object of the invention is to provide an incineratorhaving an inner casing with relatively movable walls to permit expansionand contraction due to varying temperatures, the inner casing beingenclosed within an outer casing and yieldably held in spaced relationfrom the walls thereof by attenuated heat radiating means to preventheat conduction from the inner to the outer casing, the space betweenthe casings receiving air under pressure for flow through air-perviousmaterial forming the inner casing walls to remove heat from suchmaterial and conduct the heat back into the interior of the innercasing; the air also serving to support combustion of refuse within theinner casing.

Another object of the invention is to provide the incinerator mentionedin the previous paragraphs with means, such as shields or deflectors,over the perforations in the inner casing walls to prevent line-of-sightheat radiation toward the'outer casing and to cause air flow paths fromthe space between the casings to and through the openings in theinnercasing walls, which paths will make the air most effective in extractingthe heat from the walls and shields and conducting such heat back intothe inner casing.

Other objects and advantages of the invention will be apparent from thefollowing description of the embodiment of the invention selected forillustration in the accompanying drawings.

The drawings FIG. 1 is a vertical sectional view taken through anincinerator formed in accordance with the invention;

FIG. 2 is a detail sectional view on an enlarged scale taken through acorner of the incinerator to show yieldable support means employedtherein; and

FIG. 3 is also a detail sectional view on an enlarged scale showing amodified form of perforation and shield construction which may be usedin the wall of the incinerator.

Description To carry out the objects outlined previously, an incinerator10 of the type shown in the drawings may be provided. This incinerator,as shown in FIG. 1, includes a wall structure forming a chamber 11 intowhich waste materials to be burned are introduced. In the form of theinvention illustrated, the wall structure forms a rectangular enclosure.It is obvious that any desired shape may be provided. One of thefeatures of this invention is to utilize a transpiration method ofcooling the wall structure. To secure this result, each wall of theenclosure is composed of an inner section 12 and an outer section 13.The sections 12 form an inner casing for the incinerator and thesections 13 form an outer casing.

The sections or walls 13 are spaced from the inner section 12 to providean air chamber 14 completely enclosing the inner casing. The walls 13are imperforate and may be formed of metal or other suitable material.The sections 12 of the inner casing have perforated inner and outerwalls 15 and 16 which are spaced from one another for the reception of afiller layer 17 former of fireproof insulating material which may be ofany suitable type such as glass, metal or mineral fibers so arranged asto provide tortuous passages therethrough and thus be air-pervious.

As shown in FIG. 3, modified walls 15' and 16 may be provided withopenings or slots 18 which may be stamped or otherwise formed. Theopenings in these walls permit air to flow from the air chamber into andthrough the insulating layer 17 to the interior of the incinerator. Thisair will support the combustion of the waste materials in the chamber11. One of the walls is formed with an opening 19, having a liner 20through which the waste materials may be introduced to the chamber 11.This opening is closed by a dor 20A. If found necessary, a burner 21 maybe located adjacent the opening for the initial ignition of materialsintroduced through the opening. Suitable fuel may be supplied to theburner through a passage 22. Valve 23 is arranged in the passage tocontrol flow of fuel to the burner. As illustrated, burner 21 mayreceive air for combustion of the fuel through openings 21Acommunicating with air chamber 14. Additional combustion air, ifrequired, may be supplied to the burner from chamber 14 through openings20 in liner 20.

In the form of the invention illustrated, all of the walls have similarconstruction and a platform 24 is arranged over the bottom wall toprevent ashes or other accumulation of noncombustible materials fromclogging the openings in the bottom wall. This bottom wall is elevatedabove the ground or the other supporting surface by a base 25 which mayform a manifold for the reception of air supplied to the incinerator bya suitable fan 26. In the form of the invention shown, this fan islocated at the back of the incinerator to be accessible for servicing.It is obvious that it could be disposed within the manifold formed bythe base 25, if desired.

During the use of the incinerator, relatively high temperatures may begenerated by the burning waste material. These temperatures may tend tocause the expansion of the walls, particularly those of the innercasing. To permit this action, the walls are joined to one another, asillustrated in FIG. 2, through movable connections provided by passingfastening elements 27 through slots or other suitable openings in thewalls 15 and 16 and angle iron elements 28 and 30 arranged at the innerand outer corners of the inner casing. Lost motion connections thusformed will permit the expansion and contraction of the walls.

The spacing of the walls of the inner casing from one another and fromthe walls of the outer casing is maintained by coiled elements 31 whichserve the dual purpose of yieldably maintaining the spacing of the wallelements and as heat dissipation means. Due to the elongatedconstruction, the conduction of the heat from within the inner casing tothe outer casing through the elements 31 will be prevented since anyheat transmitted to the elements will be dissipated into the air aroundthe elements. The outer wall surfaces will thus be kept cool.

Radiation of heat from the inner to the outer casing is also reduced byforming the walls of the inner casing with shields 33 over the openings18 is such walls. 'Ihese shields prevent direct line-of-sight radiationof heat through the inner casing Wals. They also cause the air to flowover paths designed to remove heat from the adjacent portions of thewalls. While FIG. 3 shows the shields stamped from the wall material,:such shields could also be separately formed and suitably secured tosuch Walls.

The inner casing is provided, as shown in FIG. 1, with a partition 34depending from the top wall. This partition is located adjacent to, butspaced from, the back wall 35 of the incinerator. The partitionterminates in spaced relation from the bottom wall and is provided tocause smoke and gases resulting from combustion to flow generallydownwardly within the chamber 11 and upwardly along the back wall to anoutlet stack 36 leading from the incinerator adjacent the upper end ofthe back wall 35. The stack may have a suitable cross sectionalconfiguration, i.e., either round or square, the walls being similar inconstruction to the walls of the'i ncinerator. The inner wall 37 of thestack has a doublewall construction with insulation between the wallsand an outer wall 38 spaced from the inner walls to provide acontinuation of the air chamber 14. The outer wall of the stack willthus be maintained at a, relatively low temperature.

To insure the complete combustion of the smoke and gases flowing to thestack, the back wall is provided with a smoke burner 40. This element,like element 20, is provided with openings 40' to admit air from the airchamber 14 to assist the combustion of the gases. Here again, a fixture41 for gas or other fuel may be employed. The burners 21 and 41 areconstructed with openings 21A and 41A, respectively, to receive air fromthe air chamber 14 to support the combustion of the fuel suppliedthereto.

From the foregoing description, it will be apparent that an incineratorhas been provided in which an inner casing for the combustion of wastematerials is completely enclosed in an outer casing with an air spacetherebetween. Means have also been provided to supply such air spacewith air under suitable pressure to cause a flow of air through the airspace and through the wall structure of the inner casing to remove heatfrom the materials of the walls and transmit it to the cham ber 11within such inner casing. This transfer of heat will assist in thecomplete consumption by fire of the waste materials introduced into theincinerator. The air thus serves a dual purpose of cooling the walls ofthe incinerator and supporting the combustion of waste materials withinthe incinerator. By reason of this transpiration cooling, the wallstructure may be maintained at a minimum thickness, conserving materialsand reducing the final weight of the incinerator to make it moresuitable for mobility purposes.

Iclaim:

1. Incinerator apparatus, comprising:

(a) an imperforate outer casing;

(b) an inner casing spaced from the Walls of the outer casing, saidinner casing having wall means with fireproof fibrous insulatingmaterial assembled to provide tortuous air passages therethrough; and i(c) means for introducing air under pressure into the space between theinner and outer casing, such air flowing through said tortuous airpassages of said inner casing to reduce heat flux by radiation,convection and conduction therethrough.

2. Incinerator apparatus of claim 1 in which the inner casing has spacedinner and outer perforated walls and a layer of air-pervious fireproofinsulating material therebetween. I

3. Incinerator apparatus of claim 1 in which the inner casing ismaintained in spaced relation from the outer casing by attenuated heatdissipation means.

4. Incinerator apparatus of claim 1 in which the inner casing ismaintained in spaced relation from the outer casing by coiled elongatedmetallic elements.

5. Incinerator apparatus of claim 1 in which means are provided to makethe walls of the inner casing movable relative to one another to providefor thermal expansion and contraction. v J

6. Incinerator apparatus of claim 2 in which the openings in theexterior walls of the inner casing are slots and shields are providedover the slots to resist heat flow from the slots toward the outercasing.

7. Incinerator apparatus of claim 1 in which the inner casing has atleast one ignition burner therein, a part of the air supplied to thespace between the casings being admitted to said burner to supportcombustion at said burner. I

8. Incinerator apparatus of claim 1 in which an exhaust stack leads fromthe inner casing adjacent the upper portion of one side thereof, thewalls of said stack having the same type of construction as theincinerator per se.

9. Incinerator apparatus of claim 8 in which a baffie depends from thetop wall of the inner casing in spaced relation to the entrance to saidexhaust stack and a smoke burner is disposed below the entrance to saidexhaust stack adjacent the lower end of said bafile, air from the spacebetween said inner and outer casings flowing to said smoke burner tosupport combustion at the same.

10. Incinerator apparatus of claim 2 in which the perforations in thewalls of the inner casing are slots and shields extending substantiallyparallel to the respective walls and over the slots are provided tocause air supplied to the space between the casings to flow parallel tothe walls when entering and leaving said slots to remove heat from saidwalls.

References Cited UNITED STATES PATENTS 1,625,082 4/1927 Helbig 110-723,354,847 11/1967 Clement et a1. 110-7 10 KENNETH W. SPRAGUE, PrimaryExaminer U.S. Cl. X.R. 110-56, 72

